Israeli tourists, many weeping and stunned, returned home yesterday telling of how their vacation heaven turned into a terror hell – while U.S. officials said they may have been victims of Osama bin Laden’s network.

“There’s a suspicion it was al Qaeda or else AIAI,” one Washington official told The Post, referring to the Somali-based Islamic group al-Itihaad al-Islamiya.

The official described AIAI as “a fundamentalist group with the goal of creating a fundamentalist state in the Horn of Africa” that has been operating in the area since 1996, carrying out bombings, kidnappings and assassination attempts.

Many of the Israeli tourists were at breakfast, just having checked into the 160-bed Paradise Hotel, when three terrorists rammed their car bomb into the hotel reception area and set off a deafening blast.

“It was a giant explosion. I saw a lot of people injured, covered with blood,” Mirah Basus, 28, said.

Survivors said terrified screams rang out through the hotel and they didn’t know where to flee.

Tzipora Kirman ran for the beach with her husband – then realized they might be heading into danger.

“We were afraid that there were armed terrorists who would fire on us because we were out in the open,” Kirman said.

Her husband, slightly wounded, was among the more than 60 people who were treated at hospitals.

The death toll grew to 13 yesterday, when a 10th Kenyan died of his wounds.

Three Israelis died in the attack – two young brothers, Davis and Noy Anter, 13 and 12, and Albert de Havila, 60.

The survivors had just arrived in Mombasa on package tours, expecting to spend their vacations snorkeling off the east African coast or driving through safari parks.

One Israeli family, the Shapiras, brought back a macabre memento – a videotape of the moments just before the blast.

“Welcome to Africa!” a hotel employee is shown saying in the lobby, shortly before everything turned black.

The film showed the feet of people running, then orange flames rising above the hotel.

“I can’t believe it! It’s a disaster,” one man yelled in Hebrew.

Another shouted: “God help me, where am I? I don’t believe it! I left my kids in there!”

Kenyan officials said yesterday they were holding 12 foreigners – an American woman and her Spanish husband, six Pakistanis and four Somalis – in the early stages of their probe.

But none were charged, and it was unclear what evidence there was against them. The American and her husband, picked up because they checked out of their nearby hotel shortly after the blast, were expected to be released.

Israeli investigators, who arrived with rescue workers late Thursday, were getting the full cooperation of local authorities, officials in Jerusalem said.

“It is expected in a few days we will know” who was behind the attack, a top Israeli official told The Post.

In other developments:

* Australian officials said they had issued a strong travel warning earlier this month about the dangers of a terrorist attack in Kenya.

The warning, believed to be based on British intelligence, told tourists to defer all non-essential travel to Mombasa and avoid hotels and other tourist areas.

* Kenya’s Daily Nation newspaper reported that investigators were examining possible links between the attacks and five Pakistanis and two Somalis detained Monday near Mombasa after they were found with Somali passports all issued on the same day. With Post Wire Services